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<TITLE>MPI_Register_datarep</TITLE>
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<H1 id="MPI_Register_datarep">MPI_Register_datarep</H1>
Register functions for user-defined data representations 
<H2>Synopsis</H2>
<PRE>
int MPI_Register_datarep(ROMIO_CONST char *datarep,
                         MPI_Datarep_conversion_function * read_conversion_fn,
                         MPI_Datarep_conversion_function * write_conversion_fn,
                         MPI_Datarep_extent_function * dtype_file_extent_fn, void *extra_state)
</PRE>
<H2>Input Parameters</H2>
<DL>
<DT><B>datarep </B> <DD> data representation name (string)

<DT><B>read_conversion_fn </B> <DD> function invoked to convert from file representation to
native representation (function)

<DT><B>write_conversion_fn </B> <DD> function invoked to convert from native representation to
file representation (function)

<DT><B>dtype_file_extent_fn </B> <DD> function invoked to get the exted of a datatype as represented
in the file (function)

<DT><B>extra_state </B> <DD> pointer to extra state that is passed to each of the
three functions
</DL>
<P>
<H2>Notes</H2>
This function allows the user to provide routines to convert data from
an external representation, used within a file, and the native representation,
used within the CPU.  There is one predefined data representation,
<tt>external32</tt>.  Please consult the MPI-2 standard for details on this
function.
<P>
<H2>Notes for Fortran</H2>
All MPI routines in Fortran (except for <tt>MPI_WTIME</tt> and <tt>MPI_WTICK</tt>) have
an additional argument <tt>ierr</tt> at the end of the argument list.  <tt>ierr
</tt>is an integer and has the same meaning as the return value of the routine
in C.  In Fortran, MPI routines are subroutines, and are invoked with the
<tt>call</tt> statement.
<P>
All MPI objects (e.g., <tt>MPI_Datatype</tt>, <tt>MPI_Comm</tt>) are of type <tt>INTEGER
</tt>in Fortran.
<P>
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